Hi,

I am an electronics enthusiast and am trying to build a circuit which senses the light from the sun. When the light intensity of the sun reduces (during sunset) below a certain level it triggers on a light.

I was thinking of using an LDR since precision is not required here. The output of the LDR is compared with LM311 voltage comparator.

The LM311 is then connected to a NOT gate to invert it.

I am wondering what the output at NOT gate will be. And further can this output be used to trigger a switch for the lighting the AC bulb??


Thanks in advance!

 

Hi,

I am an electronics enthusiast and am trying to build a circuit which senses the light from the sun. When the light intensity of the sun reduces (during sunset) below a certain level it triggers on a light.

I was thinking of using an LDR since precision is not required here. The output of the LDR is compared with LM311 voltage comparator.

The LM311 is then connected to a NOT gate to invert it.

I am wondering what the output at NOT gate will be. And further can this output be used to trigger a switch for the lighting the AC bulb??


Thanks in advance!

Why bother to use a NOT gate? You could reverse the operation of the comparator by swapping the connections to the comparator inputs.

Please post a schematic of your proposed circuit.

 

I agree, you don't need a gate. But you will likely need a MOSFET, SSR, relay or something to switch the load. A comparator can barely sink enough current for an LED, and should be used to trigger a current switching device of some kind.

You do know, of course, that you're building a device one can buy for a few dollars at the hardware store.